Yeah be good to know when do you call it empty and call for road service. When truly dead or just basically dead.I have gotten to 4.8 extra miles from 0% SoC.
I have not pushed it further... but, have noted that (while our bikes don't get hobbled for a low SoC down to 0%)... it does slow down after a mile past 0% SoC - gradually and continually. I noticed a change to 13 mph at around 1 extra mile past 0% SoC down to 8mph (is the lowest I've seen it slow me down.)
We should probably see what ones might work with our bikes. But again I am guess the computer will reject it for DC of any speed.I have "heard of" some tow trucks carrying DCF converting batteries around - but never seen any as it would be a considerable cost to support EVs.
That said, there are some EVs that can charge back (like they brought you a can of gas.)